Combustor and combustor array

ABSTRACT

A combustor includes a distal end portion which forms a nozzle extending along an axis and opening at a distal end; an intermediate portion having a mixing surface which defines a mixing space in which air and fuel are mixed, by gradually expanding to an outer side in a radial direction of the axis from the nozzle to a rear, behind the distal end portion; a proximal end portion which forms a fuel space to which fuel is supplied from outside, behind the intermediate portion; and a plurality of air introduction pipes which penetrate the proximal end portion in a direction of the axis, have a distal end communicating with the mixing space, are arranged in a circumferential direction of the axis to surround the axis, and have a fuel supply hole formed on an inner side in a radial direction of the axis to communicate with the fuel space.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to a combustor and a combustor array.

Priority is claimed on Japanese Patent Application No. 2019-043169,filed Mar. 8, 2019, the content of which is incorporated herein byreference.

Description of Related Art

In general, in a combustor, fuel injected from a fuel nozzle is mixedand burned inside a cylindrical body to form a flame inside thecylindrical body. More specifically, the fuel nozzle includes a firstnozzle disposed on a central axis of the combustor, and a plurality ofsecond nozzles disposed around the first nozzle in a circumferentialdirection. Fuel is injected from the first nozzle. The fuel burns in thesurrounding air. As a result, a diffusion flame is formed. On the otherhand, a premixed gas in which fuel and air are mixed in advance isejected from the second nozzles. When the diffusion flame touches thepremixed gas, a premixed flame is formed.

Here, in the combustor as described above, one premixed flame extendingin an axial direction is formed starting from the first nozzle. For thisreason, the flame length tends to increase in the axial direction. Whenthe length of the flame increases, since a retention time of the flamein the combustor also increases, there is a likelihood that thegeneration of NOx will be promoted. Thus, there is an increasing demandfor a combustor capable of reducing the length of the flame, while theoutput is maintained.

In this way, as a combustor capable of reducing the flame size, forexample, an apparatus described in Patent Document 1 below has beenproposed. The combustor described in Patent Document 1 has a pluralityof tubes extending in the same direction as each other. A fuel supplyhole for injecting fuel is formed on an inner peripheral surface of eachtube, and the air and fuel flowing from an upstream side are mixed andblown out of a distal end of the tube. By igniting the air-fuel mixture,a short flame is formed starting from the distal end of each tube.

PATENT DOCUMENTS

[Patent Document 1] U.S. Pat. No. 8,112,999

SUMMARY OF THE INVENTION

However, the combustor described in Patent Document 1 adopts aconfiguration in which fuel is supplied from the inner peripheralsurface of the tube. For this reason, a region having a higher fuelconcentration than other regions is formed along the inner peripheralsurface of the tube. This may cause a phenomenon in which the flameflows backward toward an upstream side (a flashback). As a result, thereis a risk of hindering a stable operation of the combustor.

The present invention has been made to solve the above-describedproblems, and an object of the present invention is to provide acombustor and a combustor array that can be operated more stably.

A combustor according to an aspect of the present invention is equippedwith a distal end portion which forms a nozzle extending along an axisand is open at a distal end; an intermediate portion having a mixingsurface which defines a mixing space in which air and fuel are mixed,which gradually expands outward in a radial direction from the axis fromthe nozzle to a rear, behind the distal end portion; a proximal endportion which forms a fuel space to which fuel is supplied from outside,behind the intermediate portion; and a plurality of air introductionpipes which penetrate the proximal end portion in a direction of theaxis, have a distal end communicating with the mixing space, arearranged in a circumferential direction with respect to the axis tosurround the axis, and have a fuel supply hole formed on each inwardside in a radial direction of the axis to communicate with the fuelspace.

According to the aforementioned configuration, the air guided into themixing space through the air introduction pipe is mixed with fuel in themixing space to form an air-fuel mixture. By igniting the air-fuelmixture, a flame is formed on a downstream side from the nozzle of thedistal end portion. Here, the fuel supply holes are formed in each ofthe portions on the inner side in the radial direction of the pluralityof air introduction pipes, that is, portions close to the axis.Accordingly, in the mixing space, as a portion becomes closer to theaxis, the fuel concentration becomes higher. Further, since the nozzleextends along the axis, the fuel concentration is highest in a regionthrough which the axis passes, in a flame region formed on thedownstream side of the nozzle. In other words, the fuel concentration isrelatively low in an inner peripheral surface of the nozzle, an innersurface of the mixing space, and a region along the surface on anoutward side in the radial direction of each air introduction pipe. As aresult, it is possible to reduce the likelihood that flashback willoccur along these surfaces. Furthermore, according to the aforementionedconfiguration, the mixing surface gradually expands to the outer side inthe radial direction from the nozzle toward the rear. In other words,the mixing surface gradually reduces in diameter radially inward in theradial direction toward the nozzle. Therefore, for example, as comparedwith a configuration in which the mixing surface expands in the radialdirection of the axis, the fuel and air can be gradually contracted anddirected toward the nozzle, while promoting mixing of the fuel and air.As a result, a pressure loss in the mixing space can be reduced.

In the combustor, the mixing surface may be curved convexly outward inthe radial direction of the axis in a cross-sectional view including theaxis.

According to the aforementioned configuration, since the mixing surfaceis curved to be convex to the outer side in the radial direction of theaxis, the fuel and air can be more gradually contracted. Therefore, itis possible to further reduce a pressure loss in the mixing space.

In the combustor, the nozzle may extend eccentrically in the radialdirection with respect to the axis from the distal end side to the rear.

According to the aforementioned configuration, the nozzle extends whilebeing eccentric in the radial direction with respect to the axis fromthe distal end side to the rear. Therefore, for example, as comparedwith a case in which the nozzle extends linearly along the axis, moreturbulent flow components can be imparted to the flow of the fuel andair in the nozzle. As a result, the mixing of fuel and air in the nozzlecan be further promoted.

In the combustor, the air introduction pipe may extend, while beingeccentric in the radial direction with respect to an auxiliary axisextending parallel to the axis from the intermediate portion side to therear.

According to the aforementioned configuration, the air introduction pipeextends while being eccentric in the radial direction with respect tothe auxiliary axis that is a central axis of the air introduction pipe,from the intermediate portion side to the rear. Therefore, for example,as compared to a case in which the air introduction pipe extendslinearly along the auxiliary axis, more turbulent flow components can beimparted to the air flow in the air introduction pipe. As a result, itis possible to further promote mixing of fuel and air in the mixingspace.

In the combustor, the air introduction pipe may be twisted to bedirected from one side in the circumferential direction of the axistoward the other side, from the intermediate portion side to the rear.

According to the aforementioned configuration, the air introduction pipeis twisted to be directed from one side in the circumferential directionof the axis toward the other side from the intermediate portion side tothe rear. Therefore, a swirl component directed from one side in thecircumferential direction toward the other side can be imparted to theflow of the air which passes through the air introduction pipe. As aresult, it is possible to further promote mixing of fuel and air in themixing space.

In the combustor, a lightening part as a hollow part may be formed in aportion closer to an outer peripheral side than the nozzle is at thedistal end portion.

According to the aforementioned configuration, the lightening part as ahollow part is formed in a portion closer to the outer peripheral sidethan the nozzle at the distal end portion. As a result, convection isgenerated in the air exposed to a high temperature of the flame in thelightening part. Since unevenness in a temperature distribution alongthe nozzle is reduced by the convection, the flame formed from thenozzle can be more effectively held.

The combustor may further have a protruding part provided on a frontside of the proximal end portion and protruding into the mixing spacealong the axis, the fuel supply hole being formed on an outer peripheralsurface of the protruding part.

According to the aforementioned configuration, the protruding partprotruding into the mixing space along the axis is provided on the frontside of the proximal end portion. Further, the fuel supply hole isformed on the outer peripheral surface of the protruding part.Therefore, fuel can be supplied to a region in the mixing space closerto the nozzle. As a result, it is possible to further promote mixing offuel and air in the mixing space.

A combustor according to an aspect of the present invention is equippedwith a distal end portion which forms a nozzle extending along an axisand opening at a distal end; an intermediate portion which forms amixing space expanding from the nozzle in a direction intersecting theaxis behind the distal end portion; a proximal end portion which forms afuel space to which fuel is supplied from outside behind theintermediate portion; and a plurality of air introduction pipes whichpenetrate the proximal end portion in a direction of the axis, have adistal end communicating with the mixing space, and are arranged in acircumferential direction of the axis to surround the axis, in which afuel supply hole through which the fuel space and the mixing spacecommunicate with each other is formed on a surface facing the distal endside of a portion surrounded by the plurality of air introduction pipesin the proximal end portion, and an extension cylinder part, whichextends in the direction of the axis to cover the fuel supply hole froma side of the outer periphery and has an air hole formed to communicatewith the mixing space, is provided on the surface facing the distal endside.

According to the aforementioned configuration, the air guided into themixing space through the air introduction pipe is mixed with fuel in themixing space to form an air-fuel mixture. By igniting the air-fuelmixture, a flame is formed on a downstream side from the nozzle of thedistal end portion. Here, the fuel supply hole is formed on a surfacefacing the distal end side of the portion surrounded by the plurality ofair introduction pipes in the proximal end portion. That is, the fuel isinjected from the fuel supply hole in the direction of the axis.Further, the fuel supply hole is covered with the extension cylinderpart from the outer peripheral side. In addition, in the extensioncylinder part, an air hole through which the mixing space communicateswith the space is formed on the inner peripheral side of the extensioncylinder part. Therefore, after mixing the fuel and air to a certainextent in the space on the side of the inner periphery of the extensioncylinder part, the air-fuel mixture can be supplied to the mixing space.That is, it is possible to further promote mixing of fuel and air in themixing space.

Furthermore, since the fuel supply part is provided along the axis, thefuel concentration increases in the mixing space as the portion iscloser to the axis. Therefore, in a flame region formed on thedownstream side of the nozzle, a fuel concentration becomes the highestin a region through which the axis passes. In other words, the fuelconcentration is relatively low on the inner peripheral surface of thenozzle, the inner surface of the mixing space, and a region along thesurface on an outer side in the radial direction of each airintroduction pipe. As a result, it is possible to reduce the likelihoodthat flashback occurs along these surfaces.

A combustor array according to an aspect of the present invention has aplurality of combustors according to any one of the above aspects. Theplurality of combustors are arranged in the plural in a plane orthogonalto the axis.

According to the aforementioned configuration, it is possible to providea combustor array that has a high output and can be stably operated, byarranging a plurality of combustors in which the likelihood ofoccurrence of flashback is reduced.

In the combustor array, the plurality of combustors may be arranged in agrid shape in the plane orthogonal to the axis.

In the combustor array, each of the plurality of combustors may have ahexagonal shape when viewed from the direction of the axis, and they maybe arranged in a honeycomb shape due end faces thereof coming intocontact with each other.

In the combustor array, the plurality of combustors may be arranged inan annular shape.

In the combustor array, the plurality of combustors may be arranged in astaggered manner so that positions of the axis differ from each other inthe plane orthogonal to the axis.

In the combustor array, the plurality of combustors may be disposedalong a curved concave surface which becomes convex from one side towardthe other side.

According to the aforementioned configuration, the flame distribution ismade uniform and a more stable flame can be obtained.

According to an aspect of the present invention, it is possible toprovide a combustor and a combustor array capable of being operated morestably.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view showing a configuration of a combustor arrayaccording to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view showing the configuration of thecombustor according to the first embodiment of the present invention.

FIG. 3 is a cross-sectional view showing a configuration of a combustoraccording to a second embodiment of the present invention.

FIG. 4 is a cross-sectional view showing a configuration of a combustoraccording to a third embodiment of the present invention.

FIG. 5 is a cross-sectional view showing a configuration of a combustoraccording to a fourth embodiment of the present invention.

FIG. 6 is a plan view showing the configuration of the combustoraccording to the fourth embodiment of the present invention.

FIG. 7 is a cross-sectional view showing a configuration of a combustoraccording to a fifth embodiment of the present invention.

FIG. 8 is a cross-sectional view showing a configuration of a combustoraccording to a sixth embodiment of the present invention.

FIG. 9 is a cross-sectional view showing a configuration of a combustoraccording to a seventh embodiment of the present invention.

FIG. 10 is a plan view showing a first modified example of a combustorarray according to an embodiment of the present invention.

FIG. 11 is a plan view showing a second modified example of thecombustor array according to an embodiment of the present invention.

FIG. 12 is a plan view showing a third modified example of the combustorarray according to the embodiment of the present invention.

FIG. 13 is a plan view showing a fourth modified example of thecombustor array according to the embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION First Embodiment

A first embodiment of the present invention will be described withreference to FIGS. 1 and 2. A combustor array 100 according to thepresent embodiment is equipped with a plurality of combustors 1. Eachcombustor 1 is a small device that forms a small-size flame. That is,the combustor array 100 is configured as a so-called micro flamecombustor.

More specifically, as shown in FIG. 1, the combustor array 100 isequipped with a plurality of (9) combustors 1 arranged in a grid shapein a plane orthogonal to an axis O that is a central axis of thecombustor 1. When viewed from a direction of the axis O, the combustor 1has a rectangular (square) cross-sectional shape. Outer surfaces of apair of adjacent combustors 1 about each other without a gap.

Next, the configuration of the combustor 1 will be described withreference to FIG. 2. FIG. 1 is a cross-sectional view taken along a lineA-A of FIG. 2. As shown in FIG. 2, the combustor 1 is equipped with adistal end portion 31, an intermediate portion 32, a proximal endportion 33, and an air introduction pipe 12.

A nozzle 11 which extends along the axis O and has a distal end 11Topening outward is formed in the distal end portion 31. As shown in FIG.1, the nozzle 11 has a circular cross-sectional shape centered on theaxis O.

The intermediate portion 32 is integrally provided on a side opposite tothe distal end 11T of the distal end portion 31 in a direction of theaxis O (a rear end 11R). In the following description, a side at whichthe distal end 11T is located when viewed from the rear end 11R in thedirection of the axis O is called a “front” and a “front side”, and anopposite side thereto is called a “rear” and a “rear side”. A mixingspace 32V communicating with the nozzle 11 is formed inside theintermediate portion 32. The mixing space 32V expands in a direction (aradial direction) intersecting the axis O. More specifically, the mixingspace 32V is defined by a conical mixing surface S1 that has a diametergradually expanding outward in the radial direction from a rear end 11Rof the nozzle 11 to the rear along the axis O, and a cylindrical surfaceS2 extending in a cylindrical shape from an end edge on a rear side ofthe mixing surface S1 along the axis O. That is, the mixing space 32V isgradually reduced in diameter from the rear side toward the nozzle 11.

The proximal end portion 33 is integrally provided on the side to therear of the intermediate portion 32. A fuel space 33V as a hollow partis formed inside the proximal end portion 33. Fuel supplied from theoutside is stored in the fuel space 33V. A surface facing the front sideof the proximal end portion 33 is configured by an annular surface S3connected to the cylindrical surface S2 of the mixing space 32V and acentral surface S4 located on the inner peripheral side of the annularsurface S3. The annular surface S3 and the central surface S4 expand atthe same position in the direction of the axis O. Further, both theannular surface S3 and the central surface S4 expand in a directionorthogonal to the axis O.

The air introduction pipe 12 is a flow path that penetrates the proximalend portion 33 in the direction of the axis O. Air supplied from theoutside is guided into the aforementioned mixing space 32V through theair introduction pipe 12. A plurality (four) of air introduction pipes12 are provided to surround the axis O at intervals in thecircumferential direction. Each air introduction pipe 12 extends alongan auxiliary axis O2 that extends parallel to the axis O. An innerdiameter of the air introduction pipe 12 is constant over the entireregion in the direction of the auxiliary axis O2. End portions on afront side of each air introduction pipe 12 communicate with theabove-described mixing space 32V. End portions on the rear side of eachair introduction pipe 12 communicate with an air supply source (notshown).

Each one fuel supply hole 40 is formed on the introduction pipe innerside surface 12A, which is a portion on an inner side in the radialdirection of the axis O, in the inner peripheral surfaces of theplurality of air introduction pipes 12. The introduction pipe inner sidesurface 12A is a region facing the axis O side when the air introductionpipe 12 is viewed from the direction of the axis O. In the innerperipheral surface of the air introduction pipe 12, a region except theintroduction pipe inner side face 12A (that is, a region facing a sideopposite to the axis O) is an introduction pipe outer side surface 12B.Each fuel supply hole 40 communicates with the fuel space 33V and thespace inside the air introduction pipe 12. The fuel stored in the fuelspace 33V is guided into the air introduction pipe 12 through the fuelsupply hole 40.

Next, the operation of the above-described combustor 1 will bedescribed. When operating the combustor 1, fuel and air are supplied tothe combustor 1, respectively. Air flows from the rear toward the frontthrough the plurality of air introduction pipes 12. Fuel is supplied(sprayed) into the air flow from the fuel space 33V through theaforementioned fuel supply hole 40. The fuel flows from the rear towardthe front along the introduction pipe inner side surface 12A in the airintroduction pipe 12. Thereafter, the fuel and air are mixed in themixing space 32V to form a premixed gas. At this time, a region having arelatively high fuel concentration (a high concentration region X) isformed to cover the introduction pipe inner side surface 12A and thecentral surface S4 from the outside. The premixed gas is guided by themixing surface S1 of the mixing space 32V to contract toward the innerside in the radial direction of the axis O. The contracted premixed gasis guided to the outside through the nozzle 11. By igniting the premixedgas with an ignition device (not shown), a premixed flame extendingforward from the nozzle 11 is formed. When such a phenomenon occurssimultaneously in each combustor 1, the combustor array 100 operates asa micro flame combustor that forms a plurality of small-scale flames.

As described above, according to the aforementioned configuration, theair guided into the mixing space 32V through the air introduction pipe12 is mixed with fuel in the mixing space 32V to form a premixed gas. Byigniting the premixed gas, a flame is formed on a downstream side fromthe nozzle 11 of the distal end portion 31. Here, the fuel supply holes40 are formed in each of the portions on the inner side in the radialdirection of the plurality of air introduction pipes 12, that is,portions close to the axis O (the introduction pipe inner side surface12A). Accordingly, in the mixing space 32V, as the portion is closer tothe axis O, the fuel concentration becomes higher (a high concentrationregion X is formed). Further, since the nozzle 11 extends around theaxis O, the fuel concentration is highest in a region through which theaxis O passes, in a flame region formed on the downstream side of thenozzle 11. In other words, the fuel concentration is relatively low inthe inner peripheral surface of the nozzle 11, the inner surface of themixing space 32V, and ae region along the surface on an outer side inthe radial direction (the introduction pipe outer side surface 12B) ofeach air introduction pipe 12. As a result, it is possible to reduce alikelihood that flashback occurs along the surfaces. Therefore, thecombustor 1 and the combustor array 100 can be operated more stably.

Furthermore, according to the aforementioned configuration, the mixingsurface S1 gradually expands to the outer side in the radial directionfrom the nozzle 11 toward the rear. In other words, the mixing surfaceS1 is gradually reduced in diameter toward the nozzle 11 from the outerside to the inner side in the radial direction. Therefore, for example,as compared with a configuration in which the mixing surface S1 expandsin the radial direction of the axis O, the fuel and air can be graduallycontracted and directed toward the nozzle, while promoting the mixing ofthe fuel and air. As a result, the pressure loss in the mixing space 32Vcan be reduced. Therefore, the combustor 1 and the combustor array 100can be operated more stably.

In addition, according to the aforementioned configuration, by arranginga plurality of combustors 1 in which the likelihood of occurrence offlashback is reduced, it is possible to provide a combustor array 100that has a high output and can be more stably operated. In particular,according to the aforementioned configuration, the plurality ofcombustors 1 are arranged in a grid shape in a plane orthogonal to theaxis O. Therefore, the distribution of the flame in the plane orthogonalto the axis O is made uniform, and a more stable flame can be obtained.

The first embodiment of the present invention has been described above.Further, various changes and modifications can be made to theaforementioned configuration without departing from the gist of thepresent invention.

Second Embodiment

Next, a second embodiment of the present invention will be describedwith reference to FIG. 3. In addition, components similar to those ofthe first embodiment are denoted by the same reference numerals, andrepeated description will not be provided. As shown in FIG. 3, in acombustor 1 according to the present embodiment, a shape of a mixingsurface S1 b is different from that of the first embodiment. The mixingsurface S1 b has a curved surface shape that is curved to be convex tothe outer side in the radial direction of the axis O in across-sectional view including the axis O. The mixing surface S1 b issmoothly connected to a cylindrical surface S2 located on the rear side.

According to the aforementioned configuration, since the mixing surfaceS1 b is curved to be convex to the outer side in the radial direction ofthe axis O, the fuel and air can be more gradually contracted.Therefore, it is possible to further reduce a pressure loss in themixing space 32V.

The second embodiment of the present invention has been described above.Further, various changes and modifications can be made to theaforementioned configuration without departing from the gist of thepresent invention.

Third Embodiment

Subsequently, a third embodiment of the present invention will bedescribed with reference to FIG. 4. In addition, configurations similarto those of each of the aforementioned embodiments are denoted by thesame reference numerals, and repeated description will not be provided.As shown in FIG. 4, in a combustor 1 according to the presentembodiment, shapes of a nozzle 11 b and an air introduction pipe 12 bare different from each of the aforementioned embodiments. The nozzle 11b extends while being eccentric in the radial direction with respect tothe axis O from the distal end 11T toward the rear end 11R. Morespecifically, the nozzle 11 b is formed by alternately connecting aportion which is eccentric with respect to the axis O (an eccentricportion E1) and a portion centered on the axis O (a centered portionC1). Further, the eccentric portion E1 and the centered portion C1 areconnected in a smooth curved surface shape.

Furthermore, the air introduction pipe 12 b extends while beingeccentric in the radial direction with respect to the auxiliary axis O2from the intermediate portion 32 side toward the rear. Morespecifically, the air introduction pipe 12 b is formed by alternatelyconnecting a portion which is eccentric with respect to the auxiliaryaxis O2 (an eccentric portion E2) and a portion centered on theauxiliary axis O2 (a centered portion C2). Further, the eccentricportion E2 and the centered portion C2 are connected in a smooth curvedsurface shape.

According to the aforementioned configuration, the nozzle 11 b extendswhile being eccentric in the radial direction with respect to the axis Ofrom the distal end 11T side to the rear. Therefore, for example, ascompared with a case in which the nozzle 11 b extends linearly along theaxis O, more turbulent flow components can be imparted to the flow ofthe fuel and air in the nozzle 11 b. As a result, it is possible tofurther promote the mixing of fuel and air in the nozzle 11 b.

Furthermore, according to the aforementioned configuration, the airintroduction pipe 12 b extends while being eccentric in the radialdirection with respect to the auxiliary axis O2 that is the central axisof the air introduction pipe 12 b from the intermediate portion 32 sideto the rear. Therefore, for example, as compared to a case in which theair introduction pipe 12 b extends linearly along the auxiliary axis O2,more turbulent flow components can be imparted to the air flow in theair introduction pipe 12 b. As a result, it is possible to furtherpromote mixing of fuel and air in the mixing space 32V.

The third embodiment of the present invention has been described above.Further, various changes and modifications can be made to theaforementioned configuration without departing from the gist of thepresent invention.

Fourth Embodiment

Next, a fourth embodiment of the present invention will be describedwith reference to FIGS. 5 and 6. In addition, configurations similar tothose of each of the aforementioned embodiments are denoted by the samereference numerals, and repeated description will not be provided. Asshown in FIGS. 5 and 6, in the present embodiment, a configuration of anair introduction pipe 12 c is different from those of each of theaforementioned embodiments. The air introduction pipe 12 c has anupstream part 12 c 1 extending along the aforementioned auxiliary axisO2, and a downstream part 12 c 2 connected to a downstream side (a frontside) of the upstream part 12 c 1. As shown in FIG. 6, the downstreampart 12 c 2 is gradually twisted from the one side in thecircumferential direction of the axis O toward the other side, from theintermediate portion 32 side to the rear. That is, the downstream part12 c 2 is inclined with respect to the axis O in a cross-sectional viewincluding the axis O.

According to the aforementioned configuration, the air introduction pipe12 c is twisted to be directed from one side in the circumferentialdirection of the axis O toward the other side from the intermediateportion 32 side to the rear. Therefore, the swirl component directedfrom one side in the circumferential direction toward the other side canbe imparted to the flow of the air which passes through the airintroduction pipe 12 c. As a result, it is possible to further promotemixing of fuel and air in the mixing space 32V.

The fourth embodiment of the present invention has been described above.Further, various changes and modifications can be made to theaforementioned configuration without departing from the gist of thepresent invention.

Fifth Embodiment

Subsequently, a fifth embodiment of the present invention will bedescribed with reference to FIG. 7. In addition, configurations similarto those of each of the aforementioned embodiments are denoted by thesame reference numerals, and repeated description will not be provided.As shown in FIG. 7, in the present embodiment, a lightening part VL as ahollow part is formed in a portion of the distal end portion 31 on theouter peripheral side of the nozzle 11. The lightening part VL has across-sectional shape along the outer shapes of the nozzle 11 and themixing surface S1. The lightening part VL communicates with the outside.That is, air can circulate in the lightening part VL.

According to the aforementioned configuration, the lightening part VL asthe hollow part is formed in the portion closer to the outer peripheralside than the nozzle 11 at the distal end portion 31. As a result,convection is generated in the air exposed to the high temperature ofthe flame in the lightening part VL. Since the uneven temperaturedistribution along the nozzle 11 is reduced by the convection, the flameformed from the nozzle 11 can be more effectively held.

The fifth embodiment of the present invention has been described above.Further, various changes and modifications can be made to theaforementioned configuration without departing from the gist of thepresent invention.

Sixth Embodiment

Next, a sixth embodiment of the present invention will be described withreference to FIG. 8. In addition, configurations similar to those ofeach of the aforementioned embodiments are denoted by the same referencenumerals, and repeated description will not be provided. As shown inFIG. 8, in the present embodiment, a protruding part 33P protrudingtoward the mixing space 32V side along the axis O is provided on asurface facing the front side of the proximal end portion 33 (that is, acentral surface S4). The protruding part 33P has a columnar shapecentered on the axis O, and a fuel supply hole 40 b through which thefuel space 33V and the mixing space 32V communicate with each other isformed on the outer peripheral surface (a protruding part outerperipheral surface 33S). A plurality of fuel supply holes 40 b areformed at intervals in the circumferential direction of the axis O. Thatis, the fuel guided by the fuel supply hole 40 b is directly supplied(sprayed) into the mixing space 32V.

According to the aforementioned configuration, the protruding part 33Pprotruding into the mixing space 32V along the axis O is provided on thefront side of the proximal end portion 33. Further, the fuel supply hole40 b is formed on the outer peripheral surface (the protruding partouter peripheral surface 33S) of the protruding part 33P. Therefore,fuel can be supplied to a region in the mixing space 32V closer to thenozzle 11. As a result, it is possible to further promote mixing of fueland air in the mixing space 32V.

The sixth embodiment of the present invention has been described above.Further, various changes and modifications can be made to theaforementioned configuration without departing from the gist of thepresent invention.

Seventh Embodiment

Subsequently, a seventh embodiment of the present invention will bedescribed with reference to FIG. 9. In addition, configurations similarto those of each of the aforementioned embodiments are denoted by thesame reference numerals, and repeated description will not be provided.As shown in FIG. 9, in the present embodiment, a cylindrical extensioncylinder part 33T centered on the axis O is provided on a centralsurface S4 of the proximal end portion 33. Furthermore, a cylindricalouter extension cylinder part 33U centered on the axis O is provided onan annular surface S3 c of the proximal end portion 33. The fuel supplyhole 40 c is formed on the central surface S4. One fuel supply hole 40 cis formed on the axis O. A plurality of air holes 50 penetrating theextension cylinder part 33T in the radial direction are formed in theextension cylinder part 33T. The mixing space 32V and the space on theinner peripheral side of the extension cylinder part 33T communicatewith each other by the air hole 50.

According to the aforementioned configuration, the air guided into themixing space 32V through the air introduction pipe 12 is mixed with fuelin the mixing space 32V to form a premixed gas. By igniting the premixedgas, a flame is formed on a downstream side from the nozzle 11 of thedistal end portion 31. Here, the fuel supply hole 40 c is formed on asurface facing the distal end 11T side of the portion surrounded by theplurality of air introduction pipes 12 in the proximal end portion 33 (acentral surface S4). That is, the fuel is injected from the fuel supplyhole 40 c in the direction of the axis O. Further, the fuel supply hole40 c is covered with the extension cylinder part 33T from the outerperipheral side. In addition, the extension cylinder part 33T is formedwith an air hole 50 through which the mixing space 32V communicates withthe space on the inner peripheral side of the extension cylinder part.Therefore, after mixing the fuel and air to a certain extent in thespace on the inner peripheral side of the extension cylinder part 33T,the air-fuel mixture can be supplied to the mixing space 32V. That is,it is possible to further promote mixing of fuel and air in the mixingspace 32V.

Furthermore, since the fuel supply hole 40 c is provided on the axis O,the fuel concentration increases in the mixing space 32V as the portionis closer to the axis O. Therefore, in the flame region formed on thedownstream side of the nozzle 11, a fuel concentration becomes thehighest in the region through which the axis O passes. In other words,the fuel concentration is relatively low in the inner peripheral surfaceof the nozzle 11, the inner surface of the mixing space 32V, and aregion along the surface on an outer side in the radial direction ofeach air introduction pipe 12 (an introduction pipe outer side surface12B). As a result, it is possible to reduce the likelihood thatflashback occurs along these surfaces. Therefore, the combustor 1 andthe combustor array 100 can be operated more stably.

The seventh embodiment of the present invention has been describedabove. Further, various changes and modifications can be made to theaforementioned configuration without departing from the gist of thepresent invention. As a modified example common to the each of the aboveembodiments, the number of the combustors 1 included in the combustorarray 100 is not limited to nine, and may be eight or less or ten ormore. Further, the number of air introduction pipes 12 in the combustor1 is not limited to four, and may be three or less or five or more.

Furthermore, the combustors 1 in the above-described combustor array 100can also be disposed in a staggered manner as shown in FIG. 10 (a firstmodified example). Specifically, a plurality of combustors 1 arearranged in a plane orthogonal to the axis O in a staggered manner sothat the positions of the axes O are different from each other.Moreover, as shown in FIG. 11, it is also possible to form eachcombustor 1 in a hexagonal shape when viewed from the direction of theaxis O, and to arrange the combustors in a honeycomb shape by bringingtheir end faces into contact with each other (a second modifiedexample). In addition, as shown in FIG. 12, it is also possible toconfigure an annular combustor array 100 by forming outer diameters ofeach of the combustors 1 in a circular arc shape and connecting thecombustors 1 in the circumferential direction (a third modifiedexample).

Further, in each of the above-described embodiments and modifiedexamples, examples in which the combustor 1 is arranged on a plane havebeen described. However, as shown in FIG. 13, it is also possible toadopt a configuration in which the combustors 1 are arranged along acurved surface (a fourth modified example). Specifically, thesecombustors 1 are arranged along a curved concave surface that is convexfrom one to the other. Note that such a curved surface may be onecontinuous surface. It may be a polyhedron formed by a plurality ofplanes connected to each other.

While preferred embodiments of the invention have been described andillustrated above, it should be understood that these are exemplary ofthe invention and are not to be considered as limiting. Additions,omissions, substitutions, and other modifications can be made withoutdeparting from the spirit or scope of the present invention.Accordingly, the invention is not to be considered as being limited bythe foregoing description, and is only limited by the scope of theappended claims.

EXPLANATION OF REFERENCES

-   -   100 Combustor array    -   1 Combustor    -   11, 11 b Nozzle    -   11R Rear end    -   11T Distal end    -   12, 12 b, 12 c Air introduction pipe    -   12 c 1 Upstream part    -   12 c 2 Downstream part    -   12A Introduction pipe inner side surface    -   12B Introduction pipe outer side surface    -   31 Distal end portion    -   32 Intermediate portion    -   32V Mixing space    -   33 Proximal end portion    -   33P Protruding part    -   33S Protruding part outer peripheral surface    -   33T Extension cylinder part    -   33U Outer extension cylinder part    -   33V Fuel space    -   40, 40 b, 40 c Fuel supply hole    -   50 Air hole    -   C1, C2 Centered part    -   E1, E2 Eccentric part    -   O Axis    -   O2 Auxiliary axis    -   S1, S1 b Mixing surface    -   S2 Cylindrical surface    -   S3 Annular surface    -   S4 Center plane    -   VL Lightening part    -   X High concentration region

What is claimed is:
 1. A combustor comprising: a distal end portion which forms a nozzle extending along an axis and opening at a distal end; an intermediate portion having a mixing surface which defines a mixing space in which air and fuel are mixed, by gradually expanding to an outer side in a radial direction of the axis from the nozzle to a rear, behind the distal end portion; a proximal end portion which forms a fuel space to which fuel is supplied from outside, behind the intermediate portion; and a plurality of air introduction pipes which penetrate the proximal end portion in a direction of the axis, have a distal end communicating with the mixing space, are arranged in a circumferential direction of the axis to surround the axis, and have a fuel supply hole formed on each inner side in a radial direction of the axis to communicate with the fuel space.
 2. The combustor according to claim 1, wherein the mixing surface is curved to be convex to the outer side in the radial direction of the axis in a cross-sectional view including the axis.
 3. The combustor according to claim 1, wherein the nozzle extends, while being eccentric in the radial direction with respect to the axis from the distal end side to the rear.
 4. The combustor according to claim 1, wherein the air introduction pipe extends, while being eccentric in the radial direction with respect to an auxiliary axis extending parallel to the axis from the intermediate portion side to the rear.
 5. The combustor according to claim 1, wherein the air introduction pipe is twisted to be directed from one side in the circumferential direction of the axis toward the other side, from the intermediate portion side to the rear.
 6. The combustor according to claim 1, wherein a lightening part as a hollow part is formed in a portion closer to an outer peripheral side than the nozzle at the distal end portion.
 7. The combustor according to claim 1, further comprising: a protruding part provided on a front side of the proximal end portion and protruding into the mixing space along the axis, the fuel supply hole being formed on an outer peripheral surface of the protruding part.
 8. A combustor comprising: a distal end portion which forms a nozzle extending along an axis and opening at a distal end; an intermediate portion which forms a mixing space expanding from the nozzle in a direction intersecting the axis behind the distal end portion; a proximal end portion which forms a fuel space to which fuel is supplied from outside behind the intermediate portion; and a plurality of air introduction pipes which penetrate the proximal end portion in a direction of the axis, have a distal end communicating with the mixing space, and are arranged in a circumferential direction of the axis to surround the axis, wherein a fuel supply hole through which the fuel space and the mixing space communicate with each other is formed on a surface facing the distal end side of a portion surrounded by the plurality of air introduction pipes in the proximal end portion, and an extension cylinder part, which extends in the direction of the axis to cover the fuel supply hole from an outer peripheral side and has an air hole formed to communicate with the mixing space, is provided on the surface facing the distal end side.
 9. A combustor array comprising: a plurality of combustors according to claim 1, wherein the plurality of combustors are arranged in the plural in a plane orthogonal to the axis.
 10. The combustor array according to of claim 9, wherein the plurality of combustors are arranged in a grid shape at equal intervals in the plane orthogonal to the axis.
 11. The combustor array according to of claim 9, wherein each of the plurality of combustors has a hexagonal shape when viewed from the direction of the axis, and is arranged in a honeycomb shape by contacting of end faces thereof.
 12. The combustor array according to of claim 9, wherein the plurality of combustors are arranged in an annular shape.
 13. The combustor array according to of claim 9, wherein the plurality of combustors are arranged in a staggered manner so that positions of the axis differ from each other in the plane orthogonal to the axis.
 14. The combustor array according to of claim 9, wherein the plurality of combustors are arranged along a curved concave surface which is convex from one to the other. 